Interference weak NT

Me and my partner have just started playing weak NT with transfers on 1C.

1NT: 11-13 NV/ 14-16 V

We decided that after 1C -1D/H we accept the transfer with 14-16 balanced, and bid 1NT with 17-19.
However, after 1C - 1D and 2S from RHO, we have some problems describing our hands.
We have on some level decided that (after 2S):
Pass = 14-16
Double = 3 card support
2NT = 17-19
3H = 4 card support, 11-13

With a minimum with five clubs, you either make a support double or pass.

With a minimum with six clubs, you might pass and then pull partner's double to 3♣. Of course, partner is not obliged to double, but since he assumes you have ostensibly a balanced 14-16, he will double quite aggressively, at least at matchpoints.

Alternatively, play the 3♣ bid as wide-ranging, say 11-16.

You can cuebid 3♠ with (17)18+ and six clubs, and with some rare balanced 18-19 hands that have no other options, say
xxx
Ax
AXx
AKxxx

Hand with 4-card support will bid 3♥ with 14-16 balanced or 11-14 unbalanced. You will need to force to game with an unbalanced 15 count, then. If this is not acceptable, you will need to play 2NT as good/bad. But then you may need to allow the doubles to include balanced 17-18 hands without 3-card support. It is actually not standard to play support level above the 2-level of responder's suit.

If you want to play support doubles here, you may consider how you respond to it. Normally, a minimum responder just rebids his suit if he has no good alternative, as a 4-3 fit at the 2-level is ok. Here, you may prefer to play 2NT by responder as artificial, or as "to play opposite 14-16 with a stopper", maybe.

... most of the new ideas I get are pretty "boring", mostly focusing on constructive methods rather than destructive ones --- Kungsgeten